AKs line check in live 1/2 game

[Black Aces 518]

Live $1/$2, avg buyin just under $100. Playing 7 handed, 5 donks to varying degree, 1 good player and myself. The good player is a solid TAG, the others vary from wacky LAGs to complete callbox fishcakes. I have been taking a bit of a beating, bubbling the tourney before this, and being outdrawn a couple of times and getting AJ on J hi flop vs callbox fishcake who limped QQ.

Good player UTG +1 ($150) limps, folds to me in CO with AcKc and about $100. I make it $8. Stunningly, the idiot button folds, as does everyone but UTG+1.

Flop comes Ah-8h-4d. UTG+1 leads for $15. Versus every other player at the table, I would jam, and get called by A2-AQ, 77+, and XhXh. But he knows what he's doing, and I feel by raising, I turn my hand faceup, and he plays perfectly. There is a heart draw, but otherwise dry to his UTG+1 limp range, and it's headsup. So I call. Preferable? Terrible?

Turn (Ah 8h 4d) 5h. ($49)
He leads out $15 again. I have about $80 behind. My move here? I call, but am not sure what I should do.

River (Ah 8h 4d 5h) 6s. ($79)
He thinks, picks up $25, then announces "Fifty" and bets $50. I debate for a while. I say "there's no way you have a seven" and he says "no, I don't have a 7". I don't think he is valuebetting $50 on this board with 2p or even set. So he has the flush or nada, right? I kind of think he would either c/r the turn with a flush or lead more, esp if he doesn't have the nut flush, he doesn't want to risk another heart coming off.

Another player says "I know what he has, I bet he'll show." UTG+1 agrees "I'll show if you fold." This usually pushes me more towards calling, but he's good, and he knows I have some ability and knowledge, so he could be 2nd leveling. Also, he's a pretty nice guy, and it was a pretty friendly game, so he could be trying to save me more of a beating (sounds dumb if you don't play live, but happens quite a bit).

Thoughts on the river, and my line till then?